How to create ARM based Container Images with Buildx

2 min readOct 13, 2022

This is a short post on how to create container images with docker and buildx so that it’s compatible with ARM architectures such as the Apple M1 and Raspberry Pi 64 bit.

Dockerfile

We will have a simple dockerfile that runs from a alpine image and we will be installing curl:

FROM alpine:latest
LABEL maintainer "Ruan Bekker"
RUN apk --no-cache add curl

Buildx

List your current builder instances:

$ docker buildx ls
NAME/NODE        DRIVER/ENDPOINT             STATUS   PLATFORMS
default                  docker default                     running    linux/amd64, linux/386

As you can see we only have amd64 and i386 architecture support for when we build container images.

Create a build instance that supports arm64 and arm:

$ docker buildx create --name multi-arch \
  --platform "linux/arm64,linux/amd64,linux/arm/v7" \
  --driver "docker-container"

Now we can update our default builder instance:

$ docker buildx use multi-arch

Build and Push

If you want to push to your image registry (using an assumption its docker hub):

$ docker login

Now we can build and push our container image with multi-arch support to our image registry:

$ docker buildx build \
  --platform "linux/amd64,linux/arm64,linux/arm/v7" \
  --tag ruanbekker/curl:test \
  --push .

When you head over to my dockerhub repository:

https://hub.docker.com/r/ruanbekker/containers/tags

You will see the digests for each architecture that we included:

Test on Apple M1

If we test this by running a container from our container image on a Apple M1, we will see that it will use the correct digest hash:

$ docker run -it ruanbekker/curl:test sh
Unable to find image 'ruanbekker/curl:test' locally
test: Pulling from ruanbekker/curl
9b18e9b68314: Already exists
5f2095374d74: Pull complete
Digest: sha256:5d87f95ded0e7e057152f8c32d4b0b81a1e2415f2b6a2ec2ac53dd8cbbc4ab39
Status: Downloaded newer image for ruanbekker/curl:test
/ # curl
curl: try 'curl --help' or 'curl --manual' for more information

Thank You

Thanks for reading, feel free to check out my website, feel free to subscribe to my newsletter or follow me at @ruanbekker on Twitter.